变量转换

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浮点数转成整数

  • round:四舍五入
IDL>print,round(5.1),round(5.9)
IDL> 5, 6
  • ceil:向上进
IDL>print,ceil(5.1),ceil(5.9)
IDL> 6, 6
  • floor:截取整数
IDL>print,floor(5.1),floor(5.9)
IDL> 5, 5
  • 结果是long型的整数,要转换更大的数,加上/L64
  • astro_lib中的nint程序,可以代替round,而且
(1) if no absolute value exceeds 32767, then the array is returned as a type INTEGER instead of LONG
(2) NINT will work on strings, e.g. print,nint(['3.4','-0.9']) will give [3,-1], whereas ROUND() gives an error message